Raised Face Flanges (RF):
RF flanges seal with a flat gasket designed for installation between the raised faces of two mating flanges (both with raised faces). The raised faces have a prescribed texture to increase their gripping and retaining force on this flat gasket. Some users of raised face flanges specify the use of spiral wound gaskets.

Ring Type Joint Flanges (RTJ) or Ring Joint Facing Flanges (R-JF):
RTJ flanges have grooves cut into their faces which accept steel Ring Gaskets. RTJ flanges seal when tightened bolts compress the gasket between the flanges into the grooves, deforming (or "Coining") the gasket to make Intimate Contact inside the grooves, creating a metal to metal seal.
An RTJ flange may have a raised face with a ring groove machined into it. This raised face does not serve as any part of the sealing means. For RTJ flanges that seal with BX ring gaskets, the raised faces of the connected and tightened flanges may contact each other. In this case the compressed gasket will not bear additional load beyond the bolt tension, vibration and movement cannot further crush the gasket and lessen the connecting tension.

EN 1092-1:
Flanges and their joints - Circular flanges for pipes, valves, fittings and accessories, PN designated - Part 1: Steel flanges
This European standard specifies requirements for circular steel flanges in PN designations PN 2,5 to PN 400 and nominal sizes from DN 10 to DN 4000. This standard specifies the flange types and their facings, dimensions, tolerances, threading, bolt sizes, flange face surface finish, marking, materials, pressure/ temperature ratings and flange masses.

EN 1092-2:
Flanges and Their Joints - Circular Flanges for Pipes, Valves, Fittings and Accessories, PN Designated - Part 2: Cast Iron Flanges
The document specifies requirements for circular flanges made from ductile, grey and malleable cast iron for DN 10 to DN 4000 and PN 2,5 to PN 63. It also specifies the types of flanges and their facings, dimensions and tolerances, bolt sizes, surface finish of jointing faces, marking, testing, quality assurance and materials together with associated pressure/temperature (p/T) ratings.

EN 1092-3:
Flanges and their joints - Circular flanges for pipes, valves, fittings and accessories, PN designated - Part 3: Copper alloy flanges
This document specifies requirements for circular copper alloy flanges in PN designations from PN 6 to PN 40 and nominal sizes from DN 10 to DN 1800.

EN 1092-4:
Flanges and Their Joints - Circular Flanges for Pipes, Valves, Fittings and Accessories, PN Designated - Part 4: Aluminium Alloy Flanges
This standard specifies requirements for PN designated circular flanges for pipes, valves, fittings and accessories made from aluminium alloy in the range of DN 15 to DN 600 and PN 10 to PN 63. This standard specifies the types of flanges and their facings, dimensions and tolerances, bolt sizes, surface finish of faces, marking and materials together with associated P/T ratings. The flanges are intended to be used for pipework as well as for pressure vessels.

EN 1759-1:
Flanges and their joints - Circular flanges for pipes, valves, fittings and accessories, Class designated - Part 1: Steel flanges, NPS 1/2 to 24
This European Standard specifies steel flanges, Class designated. The standard lists dimensions, tolerances, materials, P/T ratings and technical delivery conditions.

EN 1759-2:
Flanges and Their Joints - Circular Flanges for Pipes, Valves, Fittings and Accessories, PN Designated - Part 2: Cast Iron Flanges
The document specifies requirements for circular flanges made from ductile, grey and malleable cast iron for DN 10 to DN 4000 and PN 2,5 to PN 63. It also specifies the types of flanges and their facings, dimensions and tolerances, bolt sizes, surface finish of jointing faces, marking, testing, quality assurance and materials together with associated pressure/temperature (p/T) ratings.

EN 1759-3:
Flanges and their joints - Circular flanges for pipes, valves, fittings and accessories, Class designated - Part 3: Copper alloy flanges
The document specifies requirements for circular copper alloy flanges in Class designations Class 150 and Class 300 and nominal sizes from DN 10 to DN 900 (NPS 1/2 bis NPS 36).

EN 1759-4:
Flanges and their joints - Circular flanges for pipes, valves, fittings and accessories, Class designated - Part 4: Aluminium alloy flanges
This standard specifies requirements for Class designated circular flanges for pipes, valves, fittings and accessories made from aluminium alloy in the range of DN 15 to DN 600 (NPS 1/2 to NPS 24) and Class 150 to Class 300. This Standard specifies the types of flanges and their facings, dimensions and tolerances, bolt sizes, surface finish of faces, marking and materials together with associated p/T ratings.

EN 1515-1:
Flanges and their joints. Bolting. Selection of bolting

EN 1515-2:
Flanges and their joints. Bolting. Classification of bolt materials for steel flanges, PN designated

EN 1515-3:
Flanges and their joints. Bolting. Classification of bolt materials for steel flanges, class designated.

ANSI/ASME B16.1 -2005
Gray Iron Pipe Flanges and Flanged Fittings: Classes 25, 125, and 250
This Standard covers Classes 25, 125, and 250 Gray Iron Pipe Flanges and Flanged Fittings. It includes:
(a) pressure-temperature ratings
(b) sizes and method of designating openings of reducing fittings
(c) marking
(d) material
(e) dimensions and tolerances
(f) bolting and gaskets
(g) coatings

ANSI/ASME B16.3 -2006
Malleable Iron Threaded Fittings: Classes 150 and 300
This Standard for threaded malleable iron fittings Classes 150, and 300 provides requirements for the following: (a) pressure-temperature ratings
(b) sizes and method of designating openings of reducing fittings
(c) marking
(d) material
(e) dimensions and tolerances
(f) threading
(g) coatings

ANSI/ASME B16.4 -2006
Gray Iron Threaded Fittings, Classes 125 and 250
This Standard for gray iron threaded fittings, Classes 125 and 250, covers (a) pressure-temperature ratings
(b) sizes and method of designating openings of reducing fittings
(c) marking
(d) material
(e) dimensions and tolerances
(f) threading
(g) coatings
Mandatory Appendix I provides table values in U.S.
Customary units.

ASME B16.5 -2009
Pipe Flanges and Flanged fittings: 1/2" through 24" NPS.
This Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, testing, and methods of designating openings for pipe flanges and flanged fittings. Included are:
• Flanges with rating class designations 150, 300, 400, 600, 900, and 1500 in sizes NPS 1/2 through NPS 24 and flanges with rating class designation 2500 in sizes NPS 1/2 through NPS 12, with requirements given in both metric and U.S. Customary units with diameter of bolts and flange bolt holes expressed in inch units.
• Flanged fittings with rating class designation 150 and 300 in sizes NPS 1/2 through NPS 24, with requirements given in both metric and U.S. Customary units with diameter of bolts and flange bolt holes expressed in inch units.
• Flanged fittings with rating class designation 400, 600, 900, and 1500 in sizes NPS 1/2 through NPS 24 and flanged fittings with rating class designation 2500 in sizes 1/2 through NPS 12 that are acknowledged in Nonmandatory Appendix E in which only U.S. Customary units are provided.

This Standard is limited to:
• Flanges and flanged fittings made from cast or forged materials
• Blind flanges and certain reducing flanges made from cast, forged, or plate materials
• Also included in this Standard are requirements and recommendations regarding flange bolting, gaskets, and joints.

ANSI/ASME B16.20 -2007
Metallic Gaskets for Pipe Flanges: Ring-Joint, Spiral-Wound, and Jacketed
This Standard covers materials, dimensions, tolerances, and markings for metal ring-joint gaskets, spiral-wound gaskets, and metal-jacketed gaskets. These gaskets are dimensionally suitable for use with flanges described in reference flange standards ASME B16.5, ASME B16.47, API Specification 6A, and ISO 10423. This Standard covers spiral-wound metal gaskets and metal-jacketed gaskets for use with raised-face and flat-face flanges.

ANSI/ASME B16.21 -2005
Nonmetallic Flat Gaskets for Pipe Flanges
This Standard covers types, sizes, materials, dimensions, tolerances, and markings for nonmetallic flat gaskets. These gaskets are dimensionally suitable for use with flanges described in the referenced flange standards.

ANSI/ASME B16.24 -2006
Cast Copper Alloy Pipe Flanges and Flanged Fittings: Classes 150, 300, 600, 900, 1500 and 2500
This Standard for cast copper alloy pipe flanges and flanged fittings covers:
(a) pressure-temperature ratings;
(b) sizes and methods of designating openings for reduced fittings;
(c) marking;
(d) materials;
(e) dimensions;
(f) bolting and gaskets;
(g) tolerances;
(h) tests.
This Standard covers pressure temperature ratings, materials, dimensions, tolerances, gaskets, and tests for Classes 150, 300, 600, 900, 1500, and 2500 Cast Copper Pipe Flanges and Flanged Fittings.

ANSI/ASME B16.34 -2009
Valves Flanged, Threaded and Welding End
This Standard applies to new construction and covers pressure.temperature ratings, dimensions, tolerances, materials, nondestructive examination requirements, testing, and marking for cast, forged, and fabricated flanged, threaded, and welding end and wafer or flangeless valves of steel, nickel-base alloys, and other alloys shown in Table 1. Wafer or flangeless valves, bolted or through-bolt types, that are installed between flanges or against a flange are treated as flanged-end valves.
Alternative rules for NPS 2 1/2 and smaller valves are given in Mandatory Appendix V.

ANSI/ASME B16.42 -1998
Ductile Iron Pipe Flanges and Flanged Fittings, Classes 150 and 300
This Standard covers minimum requirements for Class 150 and 300 cast ductile iron pipe flanges and flanged fittings. The requirements covered are as follows:
(a) pressure-temperature ratings
(b) sizes and method of designating openings
(c) marking
(d) materials
(e) dimensions and tolerances
(f) bolts, nuts, and gaskets
(g) tests Codes and Regulations.
A flange or flanged fit- ting used under the jurisdiction of the ASME Boiler and Pressure Vessel Code, the ASME Code for pressure Piping, or governmental regulation is subject to any limitation of that code or re- gulation. This includes any maximum temperature limitation, any rule governing the use of a material at low temperature, or provisions for operation at a pressure exceeding the pressure- temperature ratings in this Standard.

ANSI/ASME B16.48 -2009
Valves Flanged, Threaded and Welding End
This Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for operating line blanks in sizes NPS 1/2 through NPS 24 for installation between ASME B16.5 flanges in the 150, 300, 600, 900, 1500, and 2500 pressure classes. The dimensions are suitable for blanks made of materials listed in Table 1.